Rotor for dynamo-electric machines



G M [:ATON

ROTOR FOR DYNAMO ELECT-RIC MACHINES.

APPHCATION FILED FEB. 7, I916- Patented Sept. 7,1920.

INVENTOR Geage M fez/00 A TTORNEY g I m WITNESSES UNITED STATES PATENT OFFICE.

GEORGE M. EATON, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ROTOR FOR DYNAMIC-ELECTRIC MACHINES.

Application filed February T 0 all whom it may concern Be it known that I, GEORGE M. EATON, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Rotors for Dynamo-Electric Machines, of which the following is a specification.

My invention relates to dynam0-electric machines and particularly to the positioning of current-collecting means relative to the rotor and the bearings of the machine.

One object of my invention is to provide an arrangement of parts in a dynamo-electric machine such that a maximum amount of thedistance between the supporting bearings may be occupied by the magneticallyactive part of the rotor.

Another object of my invention is to provide a similar arrangement wherein a resilient driving connection is interposed between the magnetically-active member of a dynamo-electric machine and a pinion driven thereby.

Another object of my invention is to provide a new and effectively operating structure wherein a supporting bearing is interposed between the magnetically active member and the current-collecting member of a dynamo-electric machine.

Another object of my invention is to provide an arrangement of parts in a dynamoelectric machine such that the current-collecting means therefor shall be readily accessible, although the magnetically-active part of the machine be inclosed.

Another object of my invention is to provide means for mounting current-conducting members within a rotatably mounted shaft and for bringing leads from the current-conducting members through a plurality of openings in the shaft without causing undue heating in the metal surrounding these openings.

A further object of my invention is to provide a hollow shaft having smooth ducts without abrupt bends therein and terminating intermediate the ends of the shaft and so arranged that the shaft is not materially weakened where the outlet openings are positioned.

A further object of my invention is to provide a shaft-closing plug having a plurality of inclined ducts located in radial planes at one end and a means for indicating Specification of Letters Patent.

Patented Sept. 7, 1920.

Serial No. 76,602.

the positions of the plug ducts when the parts are properly assembled.

Figure 1 of the accompanying drawing is a side view, partially in section and partially in elevation, of a dynamo-electric machine embodying my invention. Fig. 2 is an enlarged sectional end view taken on the line IL-II of Fig. 1. Fig. 3 is a sectional side view of a plug shown in Fig. l and of which Fig. 4 is an end view. Figs. and 6 are, respectively, a side view,- partially in section, and an end view of a modified form of the plug shown in Figs. 3 and 4.

Referring particularly to Fig. 1 of the drawing, the portion of a dynamo-electric machine shown comprises a hollow shaft 1 that is rotatably mounted in a bearing 2 and has an armature 3, or other magneticallyactive member, mounted on one end and a current-collecting device 4 mounted on the other end thereof.

The armature 3 embodies a spider member 5, a core member 6 and a magnetically active winding 7 that is disposed around the periphery of the core member and is electrically connected to the current-collecting device 1 by means of a plurality of cables The hollow shaft 1 has a central duct 9 in which the conductors S are disposed and a plurality of inclined outlet ducts 10 branching from the duct 5) and through which the leads from conductors 8 are brought out. One portion of the hollow shaft 1 has a larger bore than the remaining portion and has a plug 11, of the peculiar form shown in Figs. 3 and. 4 or that shown in Figs. 5 and 6 and hereinafter more fully described, inserted into the portion of the shaft having the larger bore. One end of the plug 11 has a plurality of symmetrically-disposed ducts 12 which serve to connect the ducts 10 to the central duct 9 of the shaft. A pinion 14 is yieldingly driven by the shaft 1 through an interposed driving connection 15 and is adapted to intermesh with a jack-shaft gear wheel. 16 or other suitable mechanism. A guard 17 is provided to inclose the intermeshed gears Li and 16. The driving connection 15 comprises a driving member 26 which is rigidly mounted on the shaft 1 and is resiliently and operatively connected to a driven member 27 by means of plurality of springs The driven member 27 is rotatively mounted on the shaft 1 and is rigidly secured to the pinion l t. The slip rings at are mounted upon the member 26.

The current-collecting device any well known form but is shown as oi a slip-ring type and having a plurality of cln-rent-collecting members A, B and C mounted upon, and insulated from, the driving member and adapted to receive energy from any suitable source (not shown). lrllectrical connections are established irom the current-collecting device t to the winding 7 by means of conductors 8 which are disposed within the hollow shaft 1 and have terminals brought out therefrom to the current-collecting members A, and C through the end of the shaftl.

As illustrated in Figs. 3 and 4 the plug is provided with athreaded portion 19 at one end and its other end is tapered and provided with a plurality of'grooves 21 of semi-circular cross-section. A metallic ring 22'), having grooves that are complementary tothe grooves 21 to provide ducts 12 of circular cross-section, may be shrunk, welded or otherwise secured in place on the member. in the modification shown in Figs. 5 and 6, th. plug ll has a screw-threaded end 19 but its opposite end, instead. ot being tapered, is provided with a plurality oi small blocks 23- in lieu of the ring 22 illustrated in Figs. 8 and 4:.

ln assembling such an apparatus as have herein described, diliiculty may be encountered in causing the shalt openings 14) to register with the plug ducts l2 and, to avoid this difficulty, an adj'ustirg and indicating tube 24 is provided. The inner end of the tube 2 lis screwed upon the portion 19 of the plug 11 and its outer end i be provided w1th indicating marks or n -c tions 25, the circumferential positions of which correspond to those of the ducts 12. It follows, therefore, that the plug ll may be seated in the bore of the shalt l and then be rotatively adjusted until the ducts 12 are properly located, as indicated by he marks or projections 25. By using a de vice of this type, the plug ll may be pressed into place within the shaft 1,. a key ay 30 may be cut into the surface of the shalt 1 to position the spider member 53 thereon and a drill-jig may be so located with respect to the keyway that the drilled sha l t holes 10 will exactly register with the ducts 12 through the plug 11 and thus avoid such abrupt bends and sharp projections in the cable ducts as may abrade'the conductor in sulation.

A plurality of. branch openings 10 for bringing out the cable leads insures a shaft of greater strength than if a single opening of larger size were used. The connectors 20, which connect the winding 7 to the conductors 8, may be shorter than would be necessary it they should extend from a t may be of single cable and may be more easily braced in position, since they extend in substantially radial directions from the shaft 1. Connectors are shown in Fig. l as connecting two separate cables to a single coil in order to illustrate the fact that at least one conductor from each phase extends through each opening, for reasons to be hereinafter more fully explained, but, in actual practice, the connectors extend to a plurality of coils of the same phase in the winding 7.

ln operating, it is found that, where the connectors are brought through a plurality of openings in the shaft, excessive heating results from bringing all of the leads from any one phase through a single opening but that this harmful result may be avoided by bringing one conductor per ohase, or a mul tiple thereof, through each opening in the shaft. Fig. 2, which is a sectional. view on the line ll ll of Fig. 1, shows a suitable arrangementoi conductors in a cable which may be brought through a single opening in magnetic material without causing undue heating thereof. The several conductors a,

Z2 and 0 are designed to conduct current from the respective collecting members A, B and C which are supplied with polyphase energy. The conductor (Z is inactive and .is inserted in order to give the cable 8 a symmetrical arrangement of conductors. This same reasoning applies to thecase oil a direct-current dynamo-electric machine where the currents through the lead wire' to the successive commutator segments are rapidly established and interugted' the segments pass under the brushes. Bin arrangement such that the inflowing current is equal to the outflowing current lior each opening in the shaft avoids the heating 'which otherwise results in the iron sur rounding the shaft openings.

lit will readily be understood that with such an arrangement as l have herein described, a material economy of space available for the magnetically-active portion of the armature maybe eilected, and a current-collecting device may, at all times, be readily inspected without opening the motor casing. These features, together with others that have been hereinbelore set forth,

are of considerable importance in railwayvehicle construction. 7

lVhile I have described my invention in a simple and preferred form, it is not necessarily so limited and I desire, therefore,

that only such limitations shall be imposed thereon as are indicated in the appended claims.

I claim as my invention:

1; In a dynamo-electric machine, a hollow shalt having a relatively large internal diameter at one end and relatively small internal diameter at its other end, a magnetizable member mounted upon the end of the shaft having the larger internal diameter and currcnt collecting devices mounted upon the other end, and a plug located in said shaft and seated against the shoulder formed at the junction of the larger and the smaller bore, the shaft and the plug having laterally inclined registering ducts to receive the conductors that electrically connect the winding of the magnctizable member to the current-collecting devices.

2. The combination with a hollow shaft having a plurality of inclined lateral ducts, of a plug within said shaft provided with an adjusting and indicating device that projects beyond the end of the shaft and having a plurality of inclined lateral ducts that are adapted to register with the corresponding ducts in the shaft.

3. A conductor-supporting plug comprising a grooved cylindrical portion and an internally grooved ring portion, the grooves in said portions registering in complementary relation to form conductor-receiving ducts.

A conductor-supporting plug comprising a cylindrical member having a plurality of inclined grooves in one end thereof and means having grooves adapted to register, in complementary relation with the grooves of said cylindrical member, to form conductor-rcceiving ducts.

5. A hollow shaft having inclined lateral ducts in combination with a plug having correspoinling ducts and means for rotatively adjusting the plug and indicating when its ducts register with those of the shaft.

(3. The combination with a hollow shaft having a plurality of inclined lateral ducts and a plug having corresponding ducts, of

means for effecting registration of the shaft and plug ducts, and a plurality of conductors for out-of-phase currents, at least one of said conductors per phase being brought through each of said registering ducts.

7. The combination with a plurality of conductors for polyphase currents, of a hollow shaft having inclined lateral ducts, said conductors being so disposed in said ducts that the total outflowing current is substantially equal to the total inflowing current in each duct.

8. A dynamo-electric machine comprising a hollow shaft having a larger bore in one portion than in another portion and a plurality of inclined lateral ducts branching from the larger bore, a magnetizable core mounted upon the portion of the shaft having the larger bore, a plug located in the larger bore and having inclined lateral ducts adapted to register with the shaft ducts, a plurality of conductors extending through said registering ducts and said smaller bore, a rotor winding mounted upon said magnetizable core, a current-collecting member mounted upon said shaft and electrically connected to said winding by means of said conductors, and a bearing interposed between said rotor winding and said currentcollecting member.

9. The combination with a dynamo-electric machine having a rotor, of a tubular shaft having inclined ducts in its walls and a plug having curved ducts connecting said inclined duets with the interior of the shaft, the axes of the outlets of said ducts being substantially parallel to the axis of the shaft.

in testimony whereof I have hereunto subscribed my name this 31st day of Jan, 1916.

GEORGE M. EATON. 

